Sunlight Intercepted by Planets
The vast majority of the sun's light will never encounter matter again. What fraction reaches the major and dwarf planets?
Given the diameter in km D, and the average distance from the sun in AU, the fraction intercepted by a round object object is:
(pi*D2/4)/(4*pi*(149598000*AU)2) = ( 1 / (16 * 1495980002)) * ( D / AU )2 = 2.793E-18 * ( D / AU )2
Planet |
Diameter km |
Distance AU |
Intercepted Fraction |
Mercury |
4878 |
0.39 |
4.37e-10 |
Venus |
12104 |
0.72 |
7.89e-10 |
Earth |
12756 |
1.00 |
3.15e-10 |
Mars |
6787 |
1.52 |
5.57e-11 |
Jupiter |
142800 |
5.20 |
2.11e-09 |
Saturn |
120000 |
9.54 |
4.42e-10 |
Uranus |
51118 |
19.18 |
1.98e-11 |
Neptune |
49528 |
30.06 |
7.58e-12 |
Dwarf Planet |
|
|
|
Ceres |
975 |
2.77 |
3.46e-13 |
Pluto |
2300 |
39.44 |
9.50e-15 |
Eris |
~2700 |
67.67 |
4.45e-15 |
Total |
4.17e-09 |
||
99.99999958% of the Sun's light leaves the solar system. Half of the tiny fraction intercepted is by Jupiter, 19% by Venus, 11% by Saturn, 10% by Mercury, and 8% by Earth, with a small fraction of the tiny fraction intercepted by the other planets, dwarf planets, moons, asteroids, and Kuiper belt objects.